Researchers Identify Common Neurologic Manifestations in Fibromuscular Dysplasia

According to a comprehensive literature review published in JAMA Neurology, common and rare neurologic manifestations associated with fibromuscular dysplasia (FMD) include migraine-type headaches, tinnitus, ischemic stroke, and transient ischemic attack. In the review, the researchers also identified common diagnostic considerations and management strategies of cerebrovascular FMD.

A team of US and European researchers reviewed PubMed studies for text words “fibromuscular dysplasia” or “fibromuscular hyperplasia” and the medical subject heading term “fibromuscular dysplasia.” The objective of their review was to identify and present “the epidemiologic characteristics, management, and prognosis of the neurologic manifestations associated with cerebrovascular FMD,” including those “involving cervical or intracranial arteries.”

Articles that contained data on 1 or more epidemiologic feature, clinical characteristic, radiologic feature, or cervical or intracranial FMD outcome that were published in the last 5 years and included 15 patients or more were considered eligible for inclusion. Case reports were also eligible if they featured descriptions of unique or “noteworthy” FMD manifestations. A total of 68 studies were identified from 2788 in the initial review.

For the diagnosis of cerebrovascular FMD, the consistent description across studies involved identifying alternating arterial dilatation and constriction or focal narrowing in the absence of inflammatory or atherosclerotic lesions. In children or patients with atypical phenotypes (eg, arterial diaphragm and purely intracranial FMD), diagnosis of cerebrovascular FMD can be challenging when using radiographic imaging.

Multiple arteries are often involved in FMD, according to the studies and included case reports, and there appears to be an increase in the incidence of intracranial aneurysms and cervical artery dissection among patients with FMD.

An intronic variant (rs9349379) in the PHACTR1 gene (6p24) may also be associated with FMD, according to large-scale studies included in the analysis. Despite the genetic risk, the researchers report that fewer than 5% of FMD cases are familial.

A substantial majority of patients with FMD in the pooled analysis (70%) reported primarily migraine-type headaches, and some patients also experienced pulsatile tinnitus. Although frequently asymptomatic, neurologic symptoms of FMD included ischemic stroke and transient ischemic attack, particularly in combination with cervical artery dissection. Subarachnoid hemorrhage and intracranial hemorrhage were also sometimes associated with cerebrovascular FMD in some studies.

For the prevention of thromboembolic complications in FMD, the majority of articles on the topic suggest using antiplatelet therapy. In patients with symptomatic stenosis, available data suggest using endovascular therapy, particularly in patients under otherwise optimal medical therapy or those with an intracranial aneurysm rupture.

“Despite advancements in clinical and radiologic characterization of FMD over time, significant knowledge gaps remain that should foster clinical and pathophysiological research in the neurologic manifestations of FMD,” the researchers wrote. “International research collaborations along with inclusion of patients in registries should be promoted to gain knowledge of the mechanisms and evolution of FMD and to raise awareness among clinicians and patients about this potentially disabling condition.”

Reference

Touzé E, Southerland AM, Boulanger M, et al. Fibromuscular dysplasia and its neurologic manifestations: a systematic review [published online October 1, 2018]. JAMA Neurol. doi: 10.1001/jamaneurol.2018.2848